In the past century bicycle design has undergone tremendous development and advancement, from a cumbersome, slow, heavy conveyance of limited use and range to a sleek, sturdy, lightweight vehicle that is adaptable to a great many uses. Although the advances in bicycle design, such as improved geometry, superior tires, and lighter, stronger tubing frames, have enabled a far larger segment of the public to enjoy and utilize bicycles for recreation, there remains a larger proportion of the public that cannot or will not ride bicycles.
Bicycles require a significant energy input from the rider to achieve locomotion for any meaningful distance, and this requirement is magnified substantially if hills must be negotiated. Many individuals do not wish to exert themselves to the extent required to make the bicycle a practical means of travel. In addition, senior citizens, individuals with medical conditions that limit exertion, and others are well advised to avoid such exertion. Thus the bicycle has been limited in utilization to those having healthy, if not robust, constitutions.
In recent years the bicycle has been promoted as an alternative means of travel for commuters, one that causes no air pollution nor consumes nonrenewable petroleum resources. Unfortunately, as a practical matter the exertion required for self-locomotion by bicycle often results in perspiration and fatigue, rendering an individual less than fit for a day's work. Thus most commuters have not responded favorably to imprecations to forsake their automobile for a bicycle.
Of course, there are a large variety of motorbikes and motorcycles known in the prior art and commercially available, but these conveyances generally are based on an internal combustion, gasoline powered engine. Several manufacturers also make available small internal combustion engine kits that can be installed on existing bicycles to augment the pedaling effort of the bicycle rider. Although all of these two wheel conveyances are more energy efficient than automobiles, they are still noisy, their exhaust is usually more rife with air pollutants than the highly regulated automobile engine, and they require frequent service. Thus the motorcycle, motorbike, and motor-assisted bicycle have failed to attract a significant portion of the public that would otherwise be eager bicycle riders and users.